1. The Field of the Invention
The present invention relates generally to optical transmit and receive circuits such as an optical transceiver. More specifically, the present invention relates an optical transmit and receive circuit having multiple transmit and receive paths controlled by a single controller.
2. The Relevant Technology
Computing and networking technology have transformed our world. As the amount of information communicated over networks has increased, high speed transmission has become ever more critical. Many high speed data transmission networks rely on optical transmit and receive circuits such as optical transceivers and similar devices for facilitating transmission and reception of digital data embodied in the form of optical signals over optical fibers. Optical networks are thus found in a wide variety of high speed applications ranging from as modest as a small Local Area Network (LAN) to as grandiose as the backbone of the Internet.
Typically, data transmission in such networks is implemented by way of an optical transmitter (also referred to as an electro-optic transducer), such as a laser or Light Emitting Diode (LED). The electro-optic transducer emits light when current is passed there through, the intensity of the emitted light being a function of the current magnitude. Data reception is generally implemented by way of an optical receiver (also referred to as an optoelectronic transducer), an example of which is a photodiode. The optoelectronic transducer receives light and generates a current, the magnitude of the generated current being a function of the intensity of the received light.
Various other components are also employed by optical transmit and receive circuits to aid in the control of the optical transmit and receive components, as well as the processing of various data and other signals. For example, such optical transmit and receive circuits typically include a driver (e.g., referred to as a “laser driver” when used to drive a laser signal) configured to control the operation of the optical transmitter in response to various control inputs. The optical transmit and receive circuits also generally includes an amplifier (e.g., often referred to as a “post-amplifier”) configured to perform various operations with respect to certain parameters of a data signal received by the optical receiver. A controller circuit (hereinafter referred to as the “controller”) controls the operation of the laser driver and post amplifier.
The various components of the optical transmit and receive circuits are often implemented as Transmit Optical SubAssembly (TOSA) and Receiver Optical SubAssembly (ROSA) pairs. Each TOSA and ROSA pair typically has its own controller for controlling the operation of the laser driver and post-amplifier of the pair. Each TOSA and ROSA pair is generally implemented in a host computing system.
Most host computing systems have limited space. However, as the speed and complexity of optical networks increases, there is a corresponding need to increase the number of TOSA and ROSA pairs supported by a single host. Unfortunately, the use of a single controller for each TOSA and ROSA pair uses valuable host space, thereby limiting the number TOSA and ROSA pairs that a single host can accommodate. One solution to this has been to use larger hosts or to use multiple hosts. However, this is very expensive. In addition, larger hosts may be impractical for many networking applications in which space is at a premium.
Therefore, what would be advantageous is to further increase the number of TOSA and ROSA pairs supported by a single host, while advantageously keeping the size of the host small.